K.A. Edwards, G.A. Classen and E.H.J. Schroten
ILCA Research Report No. 6 International Livestock Centre for Africa
December 1983
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ILCA PUBLICATIONS The International Livestock Centre for Africa (ILCA) is an autonomous, non-profit making research and information centre with a mandate to improve livestock production throughout sub-Saharan Africa. The activities and publications of the centre are financed by the Consultative Group on International Agricultural Research (CGIAR). The CGIAR members which have funded ILCA to date are the International Development Research Centre, the International Fund for Agricultural Development, the United Nations Development Programme, the World Bank, and the governments of Australia, Belgium, Denmark, the Federal Republic of Germany, France, Iran, Ireland, Italy, the Netherlands, Nigeria, Norway, Saudi Arabia, Sweden, Switzerland, the United Kingdom and the United States of America. Responsibility for ILCA publications rests solely with the centre and with such other parties as may be cited as joint authors. Until 1982, the centre's two main series of scientific publications were Systems Studies and Monographs. These two series have now been superceded by the present series of Research Reports. |
ORIGINAL: ENGLISH
ABSTRACT
This report gives an insight, for non-specialists in the field, into the wide range of problems concerning water development in tropical Africa. It deals with the mechanics of the hydrological cycle, the origins of the wide variations in rainfall, the potential for water resources development in pastoral areas and low-cost methods of exploiting these resources. Problems of water quality are also covered in outline. The final chapter makes recommendations, principally covering planning and operation and maintenance. Reference is made to recent advances in the field of water resources with examples taken mainly from anglophone countries in Africa.
KEY WORDS
/Tropical Africa//pastoral hydraulic engineering//water resources//water management//hydrology//water quality//precipitation/-/surface water//runoff//ground water//water conservation//evapotranspiration//water erosion//water balance/
RESUME
Ce rapport vise à familiariser les non-spécialistes avec la large gamme des problèmes que connaît l'Afrique tropical en matière de mise en valeur de ses ressources en eau. II traite du mécanisme du cycle hydrologique, des origines des variations importantes dans la pluviométrie, du potentiel qui existe dans les régions d'élevage pour le développement des ressources en eau et des méthodes d'exploitation peu onéreuses. Les problèmes concernant la qualité de l'eau y sont également ébauchés. Dans le dernier chapitre, des recommandations sont faites principalement dans le domaine de la planification, de l'exploitation et de l'entretien. Les récents progrès accomplis en matière de mise en valeur des ressources en eau y sont évoqués et illustrés par des exemples tirés principalement de l'expérience de pays africains anglophones.
MOTS-CLES
/Afrique tropicale//hydraulique pastorale//ressources en eau//aménagement hydraulique//hydrologie//qualité de l'eau//précipitation/-/eau de surface//ruissellement//eau souterraine//conservation de l'eau//évapo-transpiration//érosion hydrique//bilan hydrique/
ISBN 92-9053-043-X
ACKNOWLEDGEMENTS
The authors would like to thank Dr Brian Wilson and Dr Martyn Butterworth for their valuable comments on the manuscript; and Dr Richard Stewart for editorial assistance.
Dr K.A. Edwards would also like to thank Dr J.S.G. McCulloch, Director, Institute of Hydrology, Wallingford, UK, for permission to undertake this assignment.
This electronic document has been scanned using optical character recognition (OCR) software and careful manual recorrection. Even if the quality of digitalisation is high, the FAO declines all responsibility for any discrepancies that may exist between the present document and its original printed version.
2.1 The tropical atmosphere
2.2 Regional climatology
2.3 Measurement of point rainfall
2.4 Estimation of areal rainfall
2.5 Frequency distribution of annual, monthly and daily rainfall
2.6 Frequency distribution of extreme values
2.7 Rainfall intensity, duration and frequency
2.8 Occult precipitation
3. The hydrological cycle and its components
3.1 The hydrological cycle
3.2 Interception and infiltration
3.3 Evaporation and transpiration
3.4 Groundwater
3.5 Runoff
3.6 Measurement of streamflow
3.7 Erosion and sedimentation
3.8 The water balance
4. The potential water resource of the pastoral areas of tropical Africa
4.2.1 The occurrence of groundwater
4.2.2 Prospecting for groundwater
4.2.3 Characteristics of the groundwater of semi-arid regions
5.1 Introduction
5.2 Hydrochemical aspects of the hydrological cycle
5.3 Major characteristics of different types of resource
5.3.1 Surface water
5.3.2 Lakes and swamps
5.3.3 Groundwater5.4 Contamination of water resources
5.5 Tolerance limits for humans and livestock
6.1 General
6.2 Surface water conservation
6.2.1 Protection of springs
6.2.2 Rainfall harvesting
6.2.3 Water spreading
6.2.4 Tanks and hafirs
6.2.5 Small dams
6.2.6 Reservoirs6.4.1 Selection of pumps
6.4.2 Power for pumping
6.4.3 Wind energy technology
6.4.4 Solar energy
7. Conclusions and recommendations
7.1 Introduction
7.2 Planning
7.3 Project planning phases
7.4 Systems analysis in planning
7.5 Forecasting problems
7.6 Operation and maintenance
7.7 Recommendations
Abbreviations used in the text
The consultative group on international agricultural research